The U.S. Department of Justice has reached out to the companies as it investigates whether the cable-industry merger is anticompetitive, Bloomberg reported, citing three people familiar with the matter.

Comcast, the largest U.S. cable provider, offered in February to buy Time Warner Cable Inc for $45.2 billion in stock. The merger would put Comcast in 19 of the 20 largest U.S. TV markets, and could give it unprecedented leverage in negotiations with content providers and advertisers.

Other media companies have also been approached, Bloomberg reported, citing one of the people familiar with the matter.

Among other issues, the antitrust division is asking about most-favored-nation clauses, the report said.

Consumer advocates and U.S. lawmakers are worried that Comcast-Time Warner Cable deal would create a company with too much power to decide what Americans can watch on television and do online, and they expect intense regulatory scrutiny of the deal.